MUTANTS AND HYBRIDS OF THE OENOTHERAS. 



25 



Tabulated analysis of the characters occurring in the various types of the hybrid 

 Onagra lamarckiana X Onagra biennis Continued. 



The stems were irregularly compressed with a zigzag outline, in a manner 

 reminiscent of those of 0. rubrinervis. The upper leaves of the rosettes and of 

 the stems were strongly convexed upwardly, due to the unequal growth of the 

 laminae and midrib. The calyx-segments were relatively shorter than in either of 

 the parents. The entire shoot of the adult plant was deeply tinged with red. 



It is to be seen from the foregoing that the hybrid 0. lamarckiana X 

 0. biennis obtained from the crosses made in New York includes four 

 distinct and separate forms, none of which are identical with the uni- 

 lateral monotypic hybrid obtained in the same cross in Amsterdam. 

 In the last-named form the qualities of the pollen -parent were fully 

 dominant throughout, while in the four types the qualities of the 

 two parents exhibit diversified mosaics of dominancy and latency 

 of the parental characteristics. 



One of the American types, No. 2.1 (PI. XVII, fig. 4), was 

 characterized by a predisposition to the attacks of a fungal parasite, 

 Aecidium peckii. The portions of the plant affected exhibited structures 

 quite similar to those of the pollen-parent when affected by the same 

 organism. Organs not directly attacked by the fungus showed such 



